The Copyright Law stipulates that copyright shall be counted from the date of completion of the work. Design, poetry, photos, etc. Can be protected as copyright, regardless of whether it is registered or not. If it is designed by others, others will own the copyright of the work from the time it is completed. The contents of copyright include the right of signature, the right of modification, the right to protect the integrity of the work, and the right to authorize the use.
If you want to use a work designed by others, it depends on what purpose it is used for. Not all uses involve copyright infringement, such as research and study. But if it is used for commercial purposes, such as selling your works, it is copyright infringement.
In short, if it is for commercial use, it is best not to use it directly. It is best to negotiate with the other party and obtain the authorization of the other party.